The present invention relates to lubricating systems generally and, more particularly, to grease lubricating systems employing an injector reset valve.
Centralized lubricating systems function to distribute oil or grease from a centralized source to a plurality of lubrication points in a machine or a group of machines. A typical centralized lubrication system includes a reservoir to store lubricant, a pump to deliver the lubricant, injectors to dispense a quantity of lubricant to lubrication points in the machine and associated fittings to connect the components.
In order for the system to operate properly, it is necessary for the injectors to function reliably. A typical injector utilizes a piston which must be reset at the end of every pump cycle. Typically, injectors reset by means of a spring which is compressed during the pressurizing portion of a pump cycle and then returned to its initial position during the depressurizing portion of a cycle. This requires that a small amount of grease be pushed back towards the pump to allow the injector piston to reset. Because grease has a higher viscosity than oil, accomplishing this becomes a problem when working with grease systems. Much higher pressures are required to push grease than to push oil.
Current commercially available grease injectors accomplish this with a large, heavy duty spring in each injector. Larger springs, however, are more costly to manufacture. Additionally, larger springs require a larger injector body to house the larger spring. This, in turn, leads to higher stock material, machining and inventory costs. As a result, current injectors designed for grease lubricating systems are significantly more expensive than similar injectors designed for oil lubricating systems.